The present invention relates to an adjustable template and more particularly to an adjustable honing template for limiting the diameter of holes made by automatic honing machines and the like.
In at least one type of automatic machine that is used for honing cylindrical parts to a diameter that is accurate within one or two ten thousandths of an inch, the honing stones are cemented into recesses in metallic or plastic stone holders that have a non-abrasive surface at the upper end of the stone and which is aligned with the abrading surface of the stone. The stone holders are long and narrow and are received in longitudinally extending slots in the sidewalls of a tubular tool body. The inside of the stone holders are tapered upwardly and outwardly and are engaged by a downwardly extending cone fixed to the bottom end of a cone rod that extends upwardly and outwardly of the tool body. A plurality of the stone holders are positioned in slots evenly spaced around the tool body. The stones are moved outwardly against the work by forcing the cone rod downwardly to cause the cone to wedge the stones outwardly. Hydraulic means is provided for moving the cone downwardly to move the stones outwardly by a predetermined amount, whereupon the cone is locked into position. This outwardly predetermined amount is usually adjusted to bring the stones adjacent the surface of the work piece. Thereafter other hydraulic means slowly feeds the cone rod downwardly while the tool is rotating to remove a few thousandths of an inch from the work. An annular template or gauge ring is positioned adjacent the upper end of the work piece in which the cylinder is being honed. The automatic machine reciprocates the tool body axially upwardly and downwardly and at the end of each upward stroke the upper end of the stone holders move into the template or gauge ring. The template or gauge ring is loosely supported, and when the stones have enlarged the cylinder diameter in the work to that of the gauge ring, the stone holders come in contact with the surface of the gauge ring to produce a torque thereon. The torque is sensed by a limit switch which causes the machine to retract the cone rod and withdraw the honing tool out of the work piece. Liquid coolant flushes particles of abrasive and metal over the surfaces of the gauge and ever since the art of honing was first developed, solid rings of a very hard material have been used to resist the abrasion. The gauge rings, even when made of the hardest available commercial materials, do not last for the honing of more than six thousand work pieces in some cases. Honing operations are usually the final operation before assembly. Any imbalance of forces during honing may produce chatter and chatter usually causes the stones to dig into the finished surfaces to ruin the parts. The experience of the honing art has been that any crack or discontinuity in the template has ruined the parts produced, and consequently there has been a firm belief that the template must be continuous and solid.
An object of the present invention is the provision of a new and improved gauge ring or template which will greatly reduce the expense incurred by the frequent replacement of hardened gauge rings.
Further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description of several preferred embodiments that are described with reference to the accompanying drawings forming a part of the specification .